I'm in the process of a keg-to-kettle conversion and I'm piecing together a weldless valve with limited success. The problem I've run into is finding SS washers that fit my 3/8" compression coupler.

One solution suggested to me was to use what I believe are galvanized bushings to set between the oring and the nut, which totally solves the problem.

My question is this:

Will using a zinc alloy or zinc coated bushing/washer effect the beer in a negative way? Flavor, poisoning, color, etc.

I've seen other posts that suggest refraining from using galvanized steel to boil in due to zinc gas produced, but this is different...both in size and scope. The service area of the bushing exposed to the beer is minute at best, as well as being totally submerged and not exposed to the flame.

Shaggyt, I ran into the same problem in finding SS washers locally. I ended up using galvanized in my mash tun.....and my hair hasn't fallen out yet.

Surprisingly, I could not find much information about galvanized metals and food safety. I did see some older non-beer related forums saying not to use it because it's poisonous......much like the argument about using aluminum.
I did find that in 1997, that galvanized metals where deemed as being safe for food preparation.....with the exception of being in contact with acidic foods. I suppose beer would fall into that category. Acidic environments cause galvanized metals to corrode and the zinc converts into zinc salts. Zinc salts are readily absorbed by the body. Extreme levels can cause mild illness in some people that include dizziness, nausea, lethargy and sleepiness. But on that same note, very little illnesses were reported with galvanized containers that fruit juices were stored in.
In 2007, after more research was conducted on galvanized metals and food safety, Weber and Charbroil grill companies completely changed over to galvanized metals in their grills........even the cooking grate.

So with that said, in my opinion, I think you'd be alright. The exposure to the galvanized metal is so minute, I don't think there would be any risk....if there is even a risk.